


The Glue That Holds Them Together

by ShadowMelter



Category: Undertale (Video Game)
Genre: Gen, w.d. gaster - Freeform
Language: English
Status: Completed
Published: 2015-12-08
Updated: 2015-12-08
Packaged: 2018-05-05 15:26:55
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,562
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5380295
Author URL: https://archiveofourown.org/users/ShadowMelter/pseuds/ShadowMelter
Summary: <blockquote class="userstuff">
              <p>Why did Frisk and Chara share a body? Sans wants to know.</p>
            </blockquote>





	The Glue That Holds Them Together

Sans really hated the kid. He hated the fact that his brother, himself, and all the monsters had reached the surface only to have it taken away less than a week later. He hated that the kid turned into genocidal maniac when they had reset. He hated that they killed his brother and everyone he cared about. He hated that he couldn’t save them. He hated that the old lady made him make that promise. He hated killing the kid and getting killed too. He REALLY hated how after he died the kid went back to their save point just to kill him again. Sans hated that he had so much hatred. 

Right now, the kid was walking towards him for the third time after having had killed him twice already. He could already feel his hatred feeding into his rage.

"that expression that you're wearing… you're really kind of a freak, huh?" 

This caused the kid to stop dead in their tracks. They looked him right in the eyes, and with a hideous grin on their face they said, “Oh Sans, are you really already resorting to petty name calling? We haven’t even started yet.” This was different. The kid never even tried to speak to him during their previous fights. Hell, the kid barely even spoke during the good timelines, and now they were stringing together full sentences? If he didn’t have this stupid grin fixed to his face he would be frowning. Why were they choosing to talk to him now?

“sorry kid, what was that? i couldn’t hear you over the sound of your own death.” With that he summoned some bones below the kid’s feet, but as they shot upward the kid dodged to the side. “Hey slow down, I want to saver the act of killing you again,” they began giggling, “No need to be so hasty.” 

“what? so now you want to talk?” Sans glared at the disgusting creature. 

“No, I want to see you suffer because I want to hear Frisk scream again.”

This caused Sans to falter, “i thought your name was Frisk.” Sans only had vague memories of previous timelines, but the kid’s name was something he did not forget. 

At first the kid stopped smiling and didn’t say anything but they quickly recovered their grin and said, “No I am not Frisk, you idiot. However, Frisk is inside my head right now begging me not to kill you. But I’m going to just so I can hear them scream some more.” What a twisted little shit. Sans felt his soul pounding.

“Wanna know the best part? Every single time when you’re about to kill me I allow Frisk to regain control over their body. You know what that means right?” They giggled some more, “It means that you’re killing poor, little, innocent Frisk, who loves you very much instead of me, over and over and over again.” They were laughing hysterically now. 

Sans felt like he was going to be sick. Had he really been killing his trapped friend this whole time? No… no, this had to be a trick. 

“i don’t know of any kind of monster that can possess a human.” 

“God, you’re so dumb. I’m not a monster I’m a human.” The kid made it sound like it was the most obvious thing in the world.

“how did you get in that body? i only see one soul.” 

The kid didn’t say anything this time. It seemed like they were getting irritated. He decided to ask one last question.

“if you’re not Frisk, what is your name,” he growled. 

“Chara,” and that’s when they struck. Catching Sans off guard, the child’s knife sliced right through him. The bottle of ketchup he kept in his coat for later consumption exploded coating him in red liquid for the third time. It made him look like he was hemorrhaging a lot of blood. Sans didn’t really know why he kept the bottle in his coat for this fight. Maybe he just wanted to pull one last prank and had hoped it would freak the kid out when they killed him. Though, now he thought perhaps the evil little demon enjoyed his apparent bleeding. 

Chara, this was something new for him to hate he thought as he faded into oblivion. 

…

He woke up gasping for air, flailing his arms as he fell off his mattress and onto the cold floor. After a lot of heavy frantic breathing he closed his eyes and took a deep breath. He was back in his room in Snowdin.   
He could hear his bother alive and well stomping around downstairs. His brother must be watching TV because he can hear Mettaton’s voice. The kid must have reset the timeline again. He couldn’t remember much of what happened during the last timeline, but the one thing that stuck with him was the name Chara. 

So the kid might not have been as in control of the situation as he had thought. That didn’t mean that the kid was innocent. In fact he had no way of confirming that they were even telling him the truth. Even if they were telling the truth and Frisk had been possessed, why did Frisk reset the timeline after they had made it to the surface? Was the one called Chara already inside of Frisk at that point or did it happen after they reset? 

Sans felt like he was somehow missing the big picture. He took a quick shortcut to his lab to go over some information before heading to Grillby’s for a bite to eat. 

He was sitting at Grillby’s bar munching on french-fries when the big picture finally slapped him across the face. Of course! How could he have been so stupid? Just because he didn’t see two souls in the kid’s body didn’t mean there weren’t two souls there. When monsters absorbed human souls they become consumed by the monster’s soul but they were technically still present, they just became intertwined with the monster’s soul. They weren’t visible but they were there. There was just one problem, humans can’t absorb souls. How did Frisk manage to absorb the one called Chara? 

Unless… They didn’t.

Sans’ hand froze above his plate of french-fries as an idea struck him. What if… What if there WAS a monster soul in Frisks’ body? A monster soul that was too weak to actually consume the human souls, but despite being too weak to consume the souls it was still attempting to intertwine the souls and therefore acting as an adhesive binding the two human souls together. He realized his hand had been hovering above the french-fries for quite some time and Grillby was looking at him funny.

“uh, hey Grillbz, just put this on my tab okay?” He hopped off the bar stool and walked to the door. Once he was outside he made a quick turn into one of his shortcuts and was instantly at his sentry post. He needed some time alone to think about this. He had a sinking feeling he knew which monster’s soul was causing this fiasco. 

Gaster.

Now that was a name he hadn’t thought about in a long time. But it made sense didn’t it? It would explain how it was possible that there were two human souls duking it out in the kid’s body, and why the kid had these time altering powers to begin with. Gaster was extremely interested in time travel during his time as the Royal Scientist, and it was his interest in time manipulation that ultimately destroyed him. He remembered that Gaster had obtained the ability to move back in time by about 5 seconds. It was a power very similar to Sans’ power, only instead of manipulating small pockets of time, Sans manipulated small pockets of space allowing him to create shortcuts.

Sans knew that despite being wiped from existence after the accident, there were still fragments of Gaster left. For instance, he was the only one who remembered that Gaster even existed. Even Alphys forgot who Gaster was and she was his assistant. Perhaps his memory was a small fragment of Gaster. So if he had a tiny piece of Gaster, who’s to say that the kid didn’t have a piece too? Now, what if that fragment also contained Gaster’s time manipulation power? Human souls were stronger than monster souls so perhaps the human souls were boosting the time manipulation ability? 

Sans wasn’t sure how the kid obtained the Gaster fragment, or how it latched onto Chara’s soul. However, he felt better after having put together a hypothesis on why there were apparently two humans sharing one body. 

He wasn’t entirely sure how he was going to test the hypothesis, and right now he had a nasty headache. He was definitely going to sneak a nap in before he went and greeted the kid. 

But first he wrote down all of these new thoughts into his notebook and placed it in his lab where he knew it would somehow be able to survive a time reset. He kept it next to the photo he had of Frisk and himself smiling on the surface. At least the thoughts in the notebook would survive a reset even if the thoughts in his head didn’t. 

There was a lot of work to do.


End file.
